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