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)(13,14,18,22)(15,17,21,19)(16,23,26,24)(20,27,28,25)(5,7)(6,9)(8,12)(10,11)(13,15)(14,19)(16,24)(17,22)(18,21)(20,25)(23,26)(27,28) involution — undirected(13,16,18,26)(14,20,22,28)(15,23,21,24)(17,25,19,27)(7,12)(9,11)(13,14)(15,17)(16,20)(18,22)(19,21)(23,25)(24,27)(26,28) involution — undirected(1,3,4,2)(6,10)(9,11)(13,17,18,19)(14,21,22,15)(16,25,26,27)(20,24,28,23)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.