The Com Guards simply paint their vehicles white for official occasions and use appropriate camouflage for combat.
Per FM: ComStar, page 17.
Shootist, CB: Miniatures Rules (p 23)
Highlander, Battle of Tukayyid (p 178)
The insignia of the Fifth Army shows a Wyvern BattleMech scaling a cliff. Per FM: ComStar, page 28.