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