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