I have added a UISearchBar to the top of my PFQueryTableViewController. I have changed the colour of the searchBar to be the colour of my app, but
UISearchBar
PFQueryTableViewController
You can simply set tintcolor of searchBar to change color of Cancel button. This is available since swift 4 so should do the trick.
let searchBar = UISearchBar(frame: ) searchBar.tintColor = .orange
Search bar cancel button and cursor color change