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