One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,8)(4,6)(5,7)(9,10)(11,17)(12,15)(13,16)(14,19)(18,23)(20,22)(21,24)(25,26,29,31)(27,34,32,28)(30,33,37,39)(35,36,40,38)(9,11,13,19)(10,14,16,17)(12,18,20,24)(15,21,22,23)(26,31)(27,35)(28,36)(30,37)(32,40)(34,38)(1,3,5,4)(2,6,7,8)(9,12,13,20)(10,15,16,22)(11,18,19,24)(14,21,17,23)(25,27,30,35,29,32,37,40)(26,28,33,38,31,34,39,36)(10,16)(14,17)(15,22)(21,23)(26,31)(28,34)(33,39)(36,38) involution — undirected(1,4,5,3)(2,6,7,8)(11,19)(14,17)(18,24)(21,23)(25,28,37,36,29,34,30,38)(26,32,39,35,31,27,33,40)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.