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