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