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