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