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