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