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)(13,14,18,22,17,21,26,23)(15,20,25,27,24,19,28,16)(5,7,9,8)(6,10,11,12)(13,15,17,24)(14,19,21,20)(16,23,27,22)(18,25,26,28)(2,4)(13,15)(14,20)(16,23)(17,24)(18,25)(19,21)(22,27)(26,28) involution — undirected(5,8,9,7)(6,10,11,12)(13,16,26,19,17,27,18,20)(14,15,23,28,21,24,22,25)(15,24)(16,27)(19,20)(25,28) 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.