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