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