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)(13,14,18,19,17,22,15,21)(16,24,25,28,26,20,23,27)(5,6)(7,11)(8,10)(9,12)(14,19)(15,18)(16,23)(21,22)(25,26)(27,28) involution — undirected(1,2,3,4)(5,7)(6,9)(8,12)(10,11)(13,15,17,18)(14,19,22,21)(16,25,26,23)(20,28,24,27)(7,12)(9,11)(13,16,15,23,17,26,18,25)(14,20,21,28,22,24,19,27)(6,10)(9,11)(13,15,17,18)(14,19,22,21)(16,25,26,23)(20,28,24,27)A 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.