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