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