I haven't read the story, but I heard about it multiple times from different sources. The only problem is, I forgot the name of the story and the name of the author, but I think it was Philip K Dick.
So the story goes something like this: in a post-apocalyptic, dystopic world, an artist goes on a journey to paint God's face. For some reason, he is the only one who can fulfill this task. The world is a desolate place, very much like in The Road. God is a physical entity who resides in the physical world and is more of an evil demiurge than a benevolent divinity.
It sounds very Philip K Dick to me, but I may be wrong.