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