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