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