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