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