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