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