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