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