If by "original" Greek pronunciation, you mean Classical Greek, it would probably be something along the lines of /en.dy.'mi.ɔːn/ if you can read IPA; if not, something like "ehn-dy-MEE-on" where the "y" is like in French "tu" or
German "über". Personally, in English I'd pronounce it /ɛn.ˈdɪm.i.ən/ or en-DIM-ee-ən like on the BtN page for the name.
"Do you not find it happens very often, that you are as gay as Garrick at dinner and then by supper-time you wonder why God made the world?"