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