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