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