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