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