You can find your swift user data in the application data directory, which depends on the OS you are using. On Windows this directory will be AppData/Local/org.swift-project. As you can install multiple swift versions on your system, you might see a directory for each of those installation. Within such a directory you will find sub directories for log, cache, and settings data.
You can also access these directories from your swift applications' File menu.
Hint: In the swift launcher wizard you can transfer settings and cache data between different swift installations.