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