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