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