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