As rob said, another nice colourful fish that would do well in your tank is the ellioti. There are really too many "colourful" fish to mention that would go into a 65gal comfortably. Your really better off researching some online or go look at some in your local store and see which you like and then let us know on here. We can then let you know if they will be ok for your tank and so on.
There are also "dwarf" cichlids like apistogramma's (1 male to 2 females) and kribensis (1 male, 1 female bur can be aggressive when breeding) which get to say 3-4 inches and them that would then give you the option to add other fish to the mix. Kribs have got amazing colours IMO.
If you wanted something that gets a little bigger, like 6-7 inches then you got things like the blue Acara and the firemouth.
Then after that you start getting to bigger cichlids like jack dempseys, again awesome colours when older and you could get a pair in your tank, or as rob said, there is the green terror, you could possible get a single red devil, nice colour and a mean attitude (they get to around 12 inches)
So many options when it comes to "colourful" fish