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