Conditional formatting cell colors for the 7 days of the week

I am putting together a list for work with all employees and their days off.

Everyone has 2 adjacent days of the week off (Sundays/Mondays or Mondays/Tuesdays, etc for a total of 7 different possibilities. Listing them as S/S, S/M, M/T, T/W, W/T, T/F, F/S I am trying to use a formula for different colors.

I am using excel 2003, and I don't know of a way to do this. The column range E4:E51 is what I'm trying to work with. Then, I'd like to take the range of C4:D51 based on those colors and match them.

The colors currently in the cells have all been done manually so you can see what the end result should look like.

Hopefully I haven't made this too "wordy" trying to explain my objective.

Thanks,
Damian