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