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