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