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