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