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