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