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)(12,20)(13,18)(14,16)(17,22)(19,24)(21,23)(25,26,32,36)(27,34,29,31)(28,35,30,33)(37,39,38,40)(1,3,5,8)(2,6,4,7)(9,11,14,13)(10,15,16,18)(12,19,22,21)(17,23,20,24)(25,27,32,29)(26,31,36,34)(28,38,30,37)(33,40,35,39)(1,2,5,4)(3,6,8,7)(10,16)(15,18)(17,20)(23,24)(25,28,32,30)(26,33,36,35)(27,37,29,38)(31,39,34,40)(9,10)(11,15)(12,17)(13,18)(14,16)(19,23)(20,22)(21,24)(25,29,32,27)(26,34,36,31)(28,37,30,38)(33,39,35,40)(1,4,5,2)(3,7,8,6)(9,12)(10,17)(11,19)(13,21)(14,22)(15,23)(16,20)(18,24)(25,30,32,28)(26,35,36,33)(27,37,29,38)(31,39,34,40)(9,13,14,11)(10,18,16,15)(12,21,22,19)(17,24,20,23)(25,31,32,34)(26,27,36,29)(28,39,30,40)(33,37,35,38)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.