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