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