There's a story in the Bible where some people supposedly saw God and they had a feast together.
Exodus 24:9-11
Then Moses, Aaron, Nadab and Abihu and 70 of the elders of Israel went up and they saw the God of Israel. There was under his feet, as it were, a pavement of sapphire stone like the very heavens for clearness. And he did not lay his hand on the chief minister the people of Israel; they beheld God and ate and drank.
I think that's as close as we're going to get as for a description.
There are other passages from Isaiah, Ezekiel, Daniel. Similar descriptions. I don't think anyone saw his face, though, because they would have died. Moses saw his back that one time.
I personally don't picture him at all. I pray and then I "see" him in how he answers those prayers, or how he cheers me up when I am down, and a lot of other ways. But that's because I am looking for him in everything and I have eyes that see.