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