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