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