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