Good looking fish! Are those plants live, or fake? Be aware that if they're live, they might not survive as your fish are known to nibble on or dig up plants.
I think just about any fish (save albinos, maybe) can change color depending on mood. They'll usually wash out if they're stressed out. However, color changing among African cichlids is a bit more complicated: they'll color up quite a bit at breeding time, but often sub-dominant males will take on a different appearance or even take on the coloration of the females of the same species. It could be that that's what's going on with your fish. However, as 1077 indicated, I definitely wouldn't rule out stress created by elevated ammonia or nitrite levels, so definitely keep monitoring those with a good liquid test kit and do water changes as needed.