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