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