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