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