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