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