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