"До побачення, друзі!"
"До побачення!" is a common neutral Ukrainian farewell phrase. Such phrases are usually not translated literally, but with a corresponding phrase, such as "Goodbye!" In Turkish, for example, there is a farewell phrase "Hoşça kal!" that literally means something like "nice staying to you," but it is translated as "Goodbye!"
The literal translation is: "till next time we see each others" - the most literal there is. I'm positive on this. "Goodbye" means more like "farewell", i.e. - I don't expect to see you again, or is very unlikely. So, much more appropriate translation would be "see you later, my friends!" I speak similar language (Ruthenian) and the root of the word is the same: збачиц, обачиц - to spot, to see someone (something).
"See you later" is a colloquial phrase that may be inappropriate in some situations, for example, in a formal conversation between a supervisor and an employee. In this situation one would use "Goodbye." The Ukrainian farewell phrase "До побачення" is more like English "Goodbye" in its usage, even though its literal translation is more like "See you later." For "See you later" we would say "Побачимось."