It made sense that the costume would prominently feature feature the colors associated with Iron Man instead of Spider-Man.
The prominence of red and gold in the comics was meant to illustrate Tony Stark’s control over Peter Parker, as the billionaire was using the teenage hero as a propaganda tool supporting Superhero Registration during Civil War.
If I’m being perfectly honest, with all due respect to the creators of the costume – J. Michael Straczynski and Ron Garney – and Ryan Meinerding’s opinion, I never really loved the original Iron Spider design, and the look that we ultimately see adapted in Avengers: Infinity War makes more sense for the context in which its portrayed.