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