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