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