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