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