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