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