Hi again, Kynguyen
Actually, all three sentences are correct.
Sentence #2, "I saw the cat jumped on the table" is correct if you think of it as a sentence with a finite dependent clause in which "that" has been omitted:
"I saw (that) the cat jumped on the table."
Sentence #1, "I saw the cat jump on the table": this sentence simply states that the cat jumped on the table and you saw it.
Sentence #3, "I saw the cat jumping on the table": in this sentence you are stressing the fact that the action was taking place when you saw it. You saw the cat at the very moment it was jumping.
Miriam