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