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