All Ryuken units paint their BattleMechs charcoal gray. The members of Ryuken-roku accent their BattleMechs and other vehicles with red.
Per FM:Draconis Combine, page 131.
The Ryuken apply the Kurita dragon crest to their BattleMechs on the left leg just above the knee and near the exhaust ports of fighters. The Ryuken insignia is a dragon curling around a Katana sword, both drawn with rich detail. The regimental insignia, laid directly against the gray of the vehicle, is a rough drawing of a hand holding a sword by the blade. Per FM: Draconis Combine, pages 126 and 131.