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)(15,23,21,20)(16,26,24,25)(17,18,27,28)(1,2)(3,4)(6,9)(10,12)(13,15,18,26,19,21,28,25)(14,20,17,24,22,23,27,16)(2,4)(13,16)(14,21)(15,22)(17,25)(18,20)(19,24)(23,28)(26,27) involution — undirected(5,7,8,11)(6,10,9,12)(13,17,18,22,19,27,28,14)(15,24,26,23,21,16,25,20)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.