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