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)(15,23)(16,27)(17,19)(18,26)(20,21)(22,25)(24,28) involution — undirected(2,3)(5,7,8,12)(6,9,10,11)(14,19)(15,24)(21,27)(22,26)(1,2,4,3)(6,10)(7,12)(13,15,25,27,17,24,18,21)(14,20,26,28,19,16,22,23)(6,10)(9,11)(13,16)(14,21)(15,26)(17,20)(18,28)(19,27)(22,24)(23,25) involution — undirected(1,3,4,2)(15,24)(16,20)(21,27)(23,28)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.