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