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)(27,29)(28,36)(30,34)(31,32)(33,39)(35,38)(37,40)(1,2)(3,4)(5,6)(7,8)(9,11,15,22)(10,16,17,20)(12,13,23,24)(14,21,18,19)(26,32)(27,34)(33,36)(35,40)(2,6)(3,7)(10,17)(12,23)(13,24)(16,20)(25,27,31,34)(26,29,32,30)(28,35,39,40)(33,37,36,38)(3,7)(4,8)(9,12,15,23)(10,18,17,14)(11,13,22,24)(16,19,20,21)(25,28,31,39)(26,33,32,36)(27,35,34,40)(29,37,30,38)(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)(26,27,32,34)(28,37,39,38)(33,35,36,40)(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)(26,34,32,27)(28,38,39,37)(33,40,36,35)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.