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