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