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