The Renegades paint their BattleMechs olive-drab with red and gold highlights.

Per Mercenaries Supplemental, page 57.

Other references:
Firestarter, Mercenaries Supplemental (color plates)


Insignia:

The unit insignia is a stylized red “R” on a black disc, trimmed in red. Per FM: Mercenaries Supplemental, page 57.