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