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