Retailers, designers, exhibitors, and brand bigwigs share their personal Vegas stories and singular stylePhotographs by Beverly Poppe   (Top) Think of The Art of Diamonds’ Naval Bhandari as the ultimate high-end gem personal shopper. “I look for the very best of the best [for clients],” explained the New York City–based buyer. “I advise them what to buy to enhance their holdings and their collections.” At the top of his list: important D-flawless type IIa diamonds.    (Inset) Exhibitor Priyanka Murthy, designer of the Arya Esha collection (and a 2015 Rising Star), was excited to see “so many qualified buyers at the show.” Also, she added, “I love to come and socialize with friends in Vegas.”   “I design my own jewelry, and I’m here as the U.S. rep of a designer from Bali,” said Cynthia S. Woo of Cyn’s Diam