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)(14,18)(15,21)(16,23)(19,24)(20,26)(22,27) involution — undirected(1,2,3,4)(13,14,16,18,17,19,23,24)(15,20,21,25,22,26,27,28)(6,10)(9,11)(14,19)(18,24)(20,26)(25,28) involution — undirected(7,12)(9,11)(13,15,16,21,17,22,23,27)(14,20,18,25,19,26,24,28)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.