You do not need a macro to do that, simply use conditional formatting.
Select the entire range of cells that you want to apply this format, then go to home tab-->conditional formatting-->New Rule-->Use a formula to determine which cells to format, then in formula field enter this( assuming that your range starts from A8, and in column A is your data validation list):
=$A8="Started" , and click on format button next to preview to pick a colour to fill the cells.
Create a second rule for the other colour, determine the cells to apply the rule with the formula :
=$A8="Completed"
And so on for other conditions...