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