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