Changing the colour of a template Slide using app script - google-apps-script

Question

I have a created a slide template in which multiple teams will use to use to create an information sheet about their respective Process. This content is intended to be produced in a standardised way.
To make things easier I have created a sheet in which key information can be input into cells to populate elements of the template.
The issue I'm having is I want each process to have a different colour scheme. Is there a way I can set a cell to the desired font or background colour in sheets and then get the template to create in that colour? or even a colour scheme?
How do I single out certain text or text boxes of the slide to set the background colour?
Desired Solution
Any help is much appreciated
// Add a custom menu to the active spreadsheet, including a separator and a sub-menu.
function onOpen(e) {
SpreadsheetApp.getUi()
.createMenu('Templates')
.addItem('Cheat Sheet', 'createNewCase')
.addToUi();
}
function createNewCase(input) {
var category = input
var ui = SpreadsheetApp.getUi();
// get active spreadsheet
var activeSpreadsheet = SpreadsheetApp.getActiveSpreadsheet();
var activeSheet = activeSpreadsheet.getActiveSheet();
// Check to ensure script being run from 'Option 1' sheet
if (activeSheet.getName() != "Sheet1") {
ui.alert("Active sheet must be 'Sheet1', terminating script");
return;
}
//Get active cell
var sourceRow = activeSheet.getActiveCell().getRow();
// Read case variables
var sourceProcess = activeSheet.getRange('A' + sourceRow).getValue();
var sourceName1 = activeSheet.getRange('B' + sourceRow).getValue();
var sourceName2 = activeSheet.getRange('C' + sourceRow).getValue();
var sourceTeam = activeSheet.getRange('D' + sourceRow).getValue();
var sourcePurpose = activeSheet.getRange('E' + sourceRow).getValue();
var sourceDef = activeSheet.getRange('F' + sourceRow).getValue();
var sourceColor = activeSheet.getRange('G' + sourceRow).getFontColor();
// Message prompt
var userChoice = ui.alert("You are about to generate a Cheat Sheet template for " + sourceProcess +"\n\nDo you wish to continue?\n\n",ui.ButtonSet.YES_NO);
if (userChoice == ui.Button.NO) {
ui.alert("Terminating script");
return;
}
//Set case document filename
var newFilename = sourceProcess + "Process Cheat Sheet"
//Get template folder
var templateFolder = DriveApp.getFolderById("1MCQn9_oiaaUt4_dNzr2EoDWkUGsYOH-O");
// Get case Template document
var docTemplate = DriveApp.getFileById("1cmm1ifvfRv7omGVmRhD0zunCngBcIY_qo2jpCA_sHV4");
var caseDocument = docTemplate.makeCopy(newFilename);
var caseDocumentID = caseDocument.getId();
var caseSlide = SlidesApp.openById(caseDocumentID);
var caseName1 = caseSlide.replaceAllText("%NAME1%", sourceName1);
var caseName2 = caseSlide.replaceAllText("%NAME2%", sourceName2);
var caseProcess = caseSlide.replaceAllText("%PROCESS%", sourceProcess);
var caseTeam = caseSlide.replaceAllText("%TEAM%", sourceTeam);
var casePurpose = caseSlide.replaceAllText("%PURPOSE%", sourcePurpose);
var caseDef = caseSlide.replaceAllText("%DEFINITION%", sourceDef);
// Record Case Document link
activeSheet.getRange('H' + (sourceRow)).setFormula('=HYPERLINK("' + caseDocument.getUrl() + '", "Cheat Sheet Template")');
}