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)(16,24)(17,18)(19,23)(20,25)(22,26)(27,28)(5,6,7,8)(10,12)(14,18)(19,21)(20,24)(26,27)(5,6)(7,8)(9,10)(11,12)(13,14)(15,21)(16,20)(17,18)(19,23)(22,27)(24,25)(26,28) involution — undirected(1,2,3,4)(5,6)(7,8)(13,15,17,23)(14,19,18,21)(16,22,25,28)(20,26,24,27)(13,16,17,25)(14,20,18,24)(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.