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