BEAUTY EMPIRE: Diane von Furstenberg’s Diane fragrance launched in June and could be the start of something big. “They want me to do color, so this is just the beginning of me being back in the beauty business,” von Furstenberg said Tuesday afternoon at Sephora at NorthPark Center in Dallas. The designer has been on a whirlwind tour to promote Diane, greeting fans in Paris, Lisbon, Warsaw, Milan, Madrid, Seattle and South Coast Plaza in Costa Mesa, Calif. She was in Miami Thursday. “I travel like Willy Loman the traveling salesman,” she said. “I’ve been everywhere — I don’t even know. We started in Europe.” Von Furstenberg’s U.S. appearances have been at Bloomingdale’s, Sephora and Nordstrom.