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