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