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