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