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