I know for sure there is an official, published version of the Hub map that the designers used to help build the set, but I can’t remember where exactly I saw it. This is an artist’s rendition of it, which is what I picture the Hub to be like.
Very useful if like me, you can never wrap your head around the layout.
I think there’s a picture in the Torchwood Archive, I’d have to look. I’m still amused that they used to have a sub.