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