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