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