How does the author use symbolism in the book, That Summer: A Novel?

One example of symbolism can be found in the cashmere sweater Diana rents for her meeting with Daisy. The sweater, a symbol of duplicity, is chosen so Diana can make herself appear to be the person she had told Daisy that she is. Because the personality Diana has created for herself is so different from who she really is, the cashmere sweater that Diana wears to the dinner party at Daisy’s house is the only thing she owns that she could wear as either personality.