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