I have an java application for which its cache gets created in under
NT Authority\Network Service
Can be found here %systemroot%\ServiceProfiles\NetworkService
Usually %systemroot% translates to "C:\Windows". "systemroot" is an environment variable in windows that holds the path "C:\Windows" depending on your Windows OS installation location.
Edit: It completely depends on an application to create its cache. But most of the developers use user's home directory to maintain applications cache.