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