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