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