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