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