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