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