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