This plugin basically just changes the style of portals in IITC.
It patches a specific function that defines the style of portals: https://github.com/IITC-CE/ingress-intel-total-conversion/blob/b75faf1972d2713f02ff89c8724309205c15b8b0/core/code/portal_marker.js#L43
Click "Add external plugin" in your IITC and paste the following link:
https://github.com/lynzrand/iitc-alternative-style/raw/master/plugin.user.js