There's no difference in meaning, for in both cases " instead " means " in place of someone or something else"
We use "instead" when it is not followed by a noun, and we use " instead of" when it is followed by a noun, a noun phrase, or a noun clause. Remember that prepositions are used to join nouns to the sentence, and that's the function of " of" in this case.
So , We say:
A: " Would you like to have some tea?"
B: " I would like coffee instead of tea.?" OR
" I would like coffee instead."
OR
A: " Let's go to singapore."
B: " I'd rather go to Japan instead." OR
I'd rather go to Japan instead of Singapore." OR
I'd rather go to Japan instead of going to Singapore."
But we cannot say " instead of " without noun following. That would be a mistake.