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