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