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