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