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