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