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