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