The First Genyosha still uses the unit's original ash-gray paint scheme, with no accents.
Per FM:Draconis Combine, page 75.
Other references:
Mad Cat Mk II, CB: Miniatures Rules (p 18)
All of the Genyosha machines sport the Genyosha crest, a black tsunami filled with stars. The dragon crest of House Kurita appears prominently displayed on the upper right leg of a BattleMech and in an appropriate spot on any other vehicle. The black tsunami full of stars appears on the upper left torso or the upper left arm. Per FM: Draconis Combine, pages 75 and 76