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