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