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