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