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