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