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