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