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