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