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