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