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