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