You would need to add more colors and change your code a bit where the mod() is used.

example:
Code:
x=a mod(5)
select case x
   Case 0
   Case 1
   Case 2
   Case 3
   Case 4
 End Select
Put your colors under the proper case and you can get 5 different sets with the example above. Of course you can play with the values to make it more or less.