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