Hence, symbols that represent both arrogance and fiery tempers would work well to symbolize the Capulet family.
Colors are often useful for symbolism. Purple is a royal color and often associated with the pomp and arrogance that can go hand-in-hand with royalty. The color orange is associated with energy and flamboyance, meaning being bold and showy the way the arrogant often behave. Finally, red is often associated with "fire, blood, war, violence," and even "power," and "aggression," so it's the perfect color to symbolize a fiery temper ("Color Symbolism and Culture").
Flowers and even other people are often used symbolically. Yellow carnations often symbolize arrogance ("Arrogance"). Plus people like Napoleon and Julius Caesar are known for their arrogance, especially Caesar's famous claim after conquering Pharmaces II of Pontus, "Veni, vidi, vici," meaning, "I came, I saw, I conquered" ("Arrogance").