The Com Guards simply paint their vehicles white for official occasions and use appropriate camouflage for combat.
Per FM: ComStar, page 17.
Black Knight, FM: Comstar (plate 2)
Archer, Battle of Tukayyid (p 167)
King Crab, Battle of Tukayyid (p 178)
The insignia of the Twelfth Army shows a shield propped up on a broadsword. Per FM: ComStar, page 42.