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