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