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