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