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