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