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