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