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