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