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)(13,14,16,22,17,21,20,27)(15,19,25,28,24,23,26,18)(5,6)(7,11)(8,10)(9,12)(13,15,17,24)(14,18,21,28)(16,26,20,25)(19,22,23,27)(2,4)(5,7)(6,9)(8,12)(10,11)(13,15)(14,19)(16,25)(17,24)(18,27)(20,26)(21,23)(22,28) involution — undirected(7,12)(9,11)(13,14,20,27,17,21,16,22)(15,23,26,28,24,19,25,18)(6,10)(9,11)(14,21)(15,24)(22,27)(25,26) 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.