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