The Invisible Man is personally my favorite Queen song of all time. Even the video is awesome!

This is basically the main bass riff of the song;
G|----------------------------|----------------------------|
D|------------------------1/3-|----------------------------|
A|-3-3-3--3-3-3-3-3-3-3-3-----|-3-3-3--3-3-3-3-3-3-3-3-----|
E|----------------------------|------------------------6/3-|

But during the bridge (the 'ha, ha, ha, hello' bit)

   G
G|------------------------------|
D|------------------------------|
A|------------------------------|
E|-3-3-3--3-3-3--3-3-3--3-3-3---|

I think that's how it goes. Mind you, it's quite a funky bass riff throughout the song.

   D                              E
G|------------------------------|------------------------------|
D|------------------------------|-2-2-2--2-2-2--2-2-2--2-2-2---|
A|-5-5-5--5-5-5--5-5-5--5-5-5---|------------------------------|
E|------------------------------|------------------------------|