Sorry for the slow reply - I've been really busy.

The degree of difficulty depends on whether you can assume that the cells with each piece of text are clumped together in groups. If they are, and if you are willing to compromise on the colours, then you could differentiate between them using conditional formatting to put borders on the cells.

If you want to go the VBA route then you'll need to loop through the cells in each column, identify each distinct value and associate a colour with that value which would be used to fill the cell's interior.

Have a go and post back if you're having problems with whichever approach you go for.