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