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