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