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