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