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