One vertex per element, one color per generator, with an edge from x to x·s.
(2,4)(6,9)(7,11)(17,25)(21,28)(23,26)(24,27) involution — undirected(5,6)(7,10)(8,9)(11,12)(13,14,19,22)(15,16,20,18)(17,26,25,23)(21,24,28,27)(1,2,3,4)(13,15,18,14,19,20,16,22)(17,23,27,21,25,26,24,28)(5,7,8,11)(6,10,9,12)(13,16,19,18)(14,20,22,15)(17,24,25,27)(21,26,28,23)(6,9)(10,12)(13,17,18,27,19,25,16,24)(14,21,20,26,22,28,15,23)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.