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