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