He actually looks nothing like this in the novel. The look of bolts on the neck, green skin, dumb and arms raised out came from the 1931 film adaptation. Jack Arnold, the makeup designer for the film, came up with that on his own. But it doesn’t remotely reflect the novel In the novel he is described as having long black hair, watery eyes, very thin yellow skin where you can see all his veins, agile and silent, as well as somewhat intelligent
I quote the novel: "His limbs were in proportion, and I had selected his features as beautiful. Beautiful! Great God! His yellow skin scarcely covered the work of muscles and arteries beneath; his hair was of a lustrous black, and flowing; his teeth of a pearly whiteness; but these luxuriances only formed a more horrid contrast with his watery eyes, that seemed almost of the same colour as the dun-white sockets in which they were set, his shrivelled complexion and straight black lips."