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