For marines, there's a minimap in the upper left corner when hud detail is set to high. And if you rather play with hud detail low, like myself, there's a slimmed down version of it in the 'NS2+ options menu'; which 99% of the servers run.
Pro Tip: subscribe and activate the 'NS2+ mod' in the 'mod menu'; so you can fiddle with it without having to afk on a server.

I don't know if anyone made a mod for an alien hud map, but i like to think it's part of the assymmetric difference between the two camps and therefore should'nt exist. But that's only my opinion ofc.