Why is Jesus made of white chocolate?
Watchtower teaches that bible passages to the effect that Jesus is coming in the clouds, refers to Jesus' coming being invisible, unseen by human eyes and discerned only by the spiritually awake, i.e. JWs. I think this is the idea they're attempting to portray by painting Jesus in a color that matches the clouds in the image. They're essentially camouflaging Jesus to blend in with the clouds to portray the Watchtower idea of him coming in the clouds invisibly. If they did not make him the same color as the clouds in the image then he would look conspicuous among the white clouds and that would disprove their claiming that coming in the clouds means coming invisibly.