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