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