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)(17,21,19,27)(20,24,23,26)(1,2)(3,4)(6,10)(11,12)(13,14)(15,23)(16,18)(17,27)(19,21)(20,25)(22,24)(26,28) involution — undirected(2,4)(5,7,9,8)(6,11,10,12)(13,15,17,24,18,25,19,26)(14,20,27,28,16,23,21,22)(1,2)(3,4)(5,8,9,7)(6,12,10,11)(13,16,18,14)(15,20,25,23)(17,21,19,27)(22,24,28,26)(2,4)(13,17,18,19)(14,21,16,27)(15,24,25,26)(20,22,23,28)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.