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