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