Random Text Color in Posts – How to Code?

I’d like to have my posts cycle through 4 to 5 different text colors. For example:

Post 1 – Red
Post 2 – Blue
Post 3 – Green
Post 4 – Purple
Post 5 – Orange
Post 6 – Red
Post 7 – Blue
Post 8 – Green
and so on.

Does anyone have a suggestion (or the code!) for the best way to accomplish this? Right now I’ve just been manually making each post the color I want it as I create it, but it would be really nice to have it happen automatically.

Thanks!