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