The Arkab Legions paint their ‘Mechs in tans and dark greens.

Per FM:Draconis Combine, page 100.

Other references:
1st Arkab Legion: Locust, CM: Kurita (p 103)


Insignia:

The Legion crest is a six-pointed star set against a half-yellow, half-black background. The Legions are not required to bear the dragon crest of House Kurita, though the commanding officer of each Arkab Legion voluntarily paints the dragon insignia on the upper left arm of his BattleMech to show the Azami allegiance to House Kurita.  Per FM: Draconis Combine, pages 100.