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