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