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