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