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