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