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