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)(13,14,17,21,16,20,18,25)(15,22,24,28,23,19,26,27)(6,9)(7,11)(13,14,17,21,16,20,18,25)(15,22,24,28,23,19,26,27)(1,2,3,4)(13,14,18,25,16,20,17,21)(15,22,26,27,23,19,24,28)(5,7,8,11)(6,10,9,12)(13,15)(14,19)(16,23)(17,24)(18,26)(20,22)(21,27)(25,28)(6,9)(10,12)(15,23)(19,22)(24,26)(27,28) 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.