One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,4)(5,6)(7,9)(8,10)(11,12)(13,14,18,20)(15,21,23,22)(16,17,25,26)(19,27,28,24)(5,7)(6,9)(8,11)(10,12)(13,15,17,24,18,23,26,27)(14,19,16,21,20,28,25,22)(2,4)(7,11)(9,12)(13,16,17,20,18,25,26,14)(15,22,24,19,23,21,27,28)(7,11)(9,12)(15,23)(19,28)(21,22)(24,27) involution — undirected(6,10)(9,12)(14,20)(16,25)(19,28)(21,22) 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.