A map of Babylon 5

The "front" part of the leading sphere has the bay entry opening into the station's axis. It is flanked by two observation domes (the two "bridges")
The Docking bay is a ringlike section around the equator of the leading sphere. Ships enter through the axis of the sphere and are "lowered" down into an empty slot in the bay.
The Cobra bays are on the three struts supporting the leading sphere.
The Med lab is a sphere shaped area snug against Blue Section.
The other sections are shaped like rings.
Blue section: Political officialdom.
Red section: Business. (I hazard a guess that the Zocalo is located here, but am uncertain)
Green section: Ambassadorial accommodations.
Grey section: Exotic alien environments; industrial areas.
Brown section: Slums and brothels.
The Garden is the hollow cylindrical area with hydroponic gardens. One often sees this in the open-air luxury restaurants.
The Core Shuttle runs down the station's axis.

Source: Cinefantastique Feb 1993
Original art by Babylon 5 graphic artist Ted Haigh
Ascii art by Richard Meikle