She's actually known for being kind of ugly. What drew so many men to her was her power and charm. But it's hard to portray hypnotizing charm in a movie so instead they portray her as hypnotizingly beautiful and exotic.

The sources we have in regards to Cleopatra were written by the Romans, her enemies and most read as follows: "For she was a woman of surpassing beauty, and at that time, when she was in the prime of her youth, she was most striking; she also possessed a most charming voice and a knowledge of how to make herself agreeable to every one. Being brilliant to look upon and to listen to, with the power to subjugate every one, even a love-sated man already past his prime, she thought that it would be in keeping with her rôle to meet Caesar, and she reposed in her beauty all her claims to the throne. She asked therefore for admission to his presence, and on obtaining permission adorned and beautified herself so as to appear before him in the most majestic and at the same time pity-inspiring guise. When she had perfected her schemes she entered the city (for she had been living outside of it), and by night without Ptolemy's knowledge went into the palace." - Dio, Roman History (XLII.34.4-6) Historians such as Plutarch who gives good profiles on ancient personalities are also unforgiving: "For her beauty, as we are told, was in itself not altogether incomparable, nor such as to strike those who saw her; but converse with her had an irresistible charm, and her presence, combined with the persuasiveness of her discourse and the character which was somehow diffused about her behaviour towards others, had something stimulating about it. There was sweetness also in the tones of her voice; and her tongue, like an instrument of many strings, she could readily turn to whatever language she pleased…" - Plutarch, Life of Antony (XXVII.2-3) I found an article from the British School at Rome stating that a wall scene from Pompeii previously thought to be Venus could be Cleopatra ( http://www.jstor.org/stable/40311128 ) this of course is speculation and has not been proved