Free Worlds League Fleet 

Bands of Marik purple encircle an otherwise unadorned hull. Across these are displayed the Marik eagle, the ship’s name and hull number, and (in an addition made by Thomas Marik) a heraldic shield. Cruisers sport lions, Carriers display a unicorn, gryphons appear on Destroyers and Frigates and Corvettes use an eagle in their unique devices.

Per AeroTech 2: Revised, WarShip Fleet Color Schemes

Other references:
Thera, Handbook: House Marik (cover)
Thera, Aerotech 2 (color plates) Thera and Eagle, Total Warfare (p. 26)