The caption just reads a Bernie Wrightson concept of the gateway.
But I'm wondering if this was to represent or show what world/dimension Gozer was in before it got called to our world. The place in the drawing looks really destroyed, lava, rubble, etc. A fantastic looking gate and some character walking towards it.
Ive heard about most facts from the movie, but this storyboard I hadnt seen. Very intriguing.