Okay

Some people refuse to believe that the mural depicts a normal Xeno and even go as far as saying there's nothing relevant portrayed in the mural at all.

I don't understand why, because to me, it's one of the clearest things in the movie.

Ridely Scott himself has said that the Deacon is neither an ancestor or a descendant of the Xenomorph, but it's cousin. Keep in mind that these are 2 different species. The mural, like the beacon, is probably a warning.