He should have a neutral face expression (which means not too aggressive, no bared fangs or something) and he should look rather young (so no grey streaked fur or something similar that makes him look old).
The fur color doesn't matter much, do what you think looks cool, but the fur should not be too short, more like that of a persian cat or Thrakhath.
And if you think you're not able to create a Kilrathi face I would even be happy about just the helmet with a black visor.
The picture can be either drawn or rendered, everything is better than what I have now.
If you want to help me with that, please PM me or post here