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)(15,23)(16,25)(17,21)(18,24)(19,22)(20,28)(26,27) involution — undirected(1,2)(3,4)(13,15,18,25,19,26,17,20)(14,16,21,23,22,28,24,27)(2,4)(6,9)(10,12)(13,16,19,28)(14,20,22,25)(15,24,26,21)(17,27,18,23)(2,4)(13,17,19,18)(14,21,22,24)(15,25,26,20)(16,27,28,23)(5,7,8,11)(6,10,9,12)(13,17,19,18)(14,21,22,24)(15,20,26,25)(16,23,28,27)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.