Rev 4:3 says god had an appearance that John actually saw.
"He was to resemble a sardine stone"
When u see a resemblance u have to actually be seeing something that has shape, size, and color. the official definition of resemblance determined that. So John didn't just metaphorically observe the personality of god, he must've actually seen a god that was colors too. There's a contingency between physical colors to spiritual personalities that can't be separated in the context of heaven as depicted in the bible.