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