It is highly debatable that veggies help with coloration. Some people swear by them, but a lot don't. I don't think they are a bad idea, but my fishs' colors were a bit muted when I fed them veggies. IME (and IMO) feed a good staple food is the best option, and then if you would like to add in a snack every now and then.
I feed NLS cichlid formula (I have tried others like omega one and hikari and find NLS to give better growth and colors) and give freeze-dried brine shrimp ever 4 or 5 days. I don't give tons of brine shrimp, just enough that most of the fish get some.
(On a side note, the above statement supporting NLS is purely my opinion based on my experience. I am in no way saying Hikari or Omega One or any other high quality food is bad. I am not trying to start any arguments or debates.)