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