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