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