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