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