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