Here’s the Solvalou fighter, your ship in the game.
The Andor Genesis, the boss ships you fight against. Sort of looks like the top part of a Cylon Base Star.
Speaking of Battlestar Galactica, the Terrazi looks like a Cylon Raider.
This Jara is sort of TIE Fighter shaped.
The Kapi has a sort of Millennium Falcon shape to it.
I can’t say this Grobda tank really looks like anything, except maybe a cross from the Galileo Shuttle from Star Trek and the land rover from Battlestar Galactica.
The port of Xevious on the Atari 7800 is what I put the most time into, when I was in junior high. I remember how thrilled I was when I bombed the Andor Genesis with a one bomb kill. I’ll have to give it a try on my 7800 emulator for RetroPie again sometime to refresh my memory. IIRC, it wasn’t a bad port and it even had the hidden flags you can reveal by bombing secret areas on the screen.