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