You can turn on color by using the 'ANSI_COLOR' directive in the citadel.rc file. There are four modes: OFF, which always turns color off; ON, which always turns it on; AUTO, which sends an enquiry to the terminal and turns color on if it discovers that the terminal supports it, and USER, which prompts each user for a color on/off setting in their configuration.
Since all modern terminals implement some sort of ANSI support, the Citadel console client no longer uses terminfo or ncurses, bur instead outputs ANSI control sequences directly.