One vertex per element, one color per generator, with an edge from x to x·s.
(5,6)(7,12)(8,10)(9,11)(14,20)(15,22)(16,24)(17,18)(21,23)(25,26) involution — undirected(1,2)(3,4)(5,7,9,8)(6,10,11,12)(13,14,19,15)(16,23,26,21)(17,22,18,20)(24,28,25,27)(2,4)(5,8,9,7)(6,10,11,12)(13,15,19,14)(16,23,26,21)(17,20,18,22)(24,28,25,27)(13,16,17,25,19,26,18,24)(14,21,22,28,15,23,20,27)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.