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