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