In Finder
- command+shift+G (or use the menu “Go -> Go to Folder…”)
- in the little panel enter “~/Library/Application Support/Eufloria” (no quotation marks, please

tilde “~”, the traditional UNIX sign for home folder, is alt+n)
- press Return
- there you are

It probably is the file named “OptionsData.bin”.
BTW there’s a folder named “CustomMaps” here

but it’s empty.
IMHO it’s not nice to put prefs in that folder, they ought to be in the in ~/Library/Preferences/ (but I’ll better collect all my peeves with the Mac version in another thread)