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