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