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