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