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