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