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