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