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