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