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