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