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