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