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