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