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