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