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