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