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