Genesis was written in the 10th-5th century BC.
Revelation was written in 68-95 AD.
That's still conjecture. You assume the two authors are in reference to the same exact entity because they are in the same book and apparently bad.
I'm not trying to get into a flame war here. So let's move on.
The Book of Job is arguably the oldest document in the western canon (older than Genesis)...
...and you are correct Revelation is one of the more recent.
The western canon contains approx 66 documents written by 44 different authors over more than 2000 years...
...and although idiom, language and cultures changed...
...they all essentially tell the same story.
The serpent is the same guy.
Another thing you should consider...
...John wrote Revelation while on the island of Patmos...
...he was a prisoner there...
...and he wrote the work using about 800 symbols from the Old Testament documents...
...as a way of getting the letter past the guards without them undrstanding it...
...so he was infact describing exactly the same guy...
...that's why he uses all his various names and titles.