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