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