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)(11,12)(13,21)(14,16)(15,17)(18,22)(19,23)(20,24)(25,26,30,33)(27,31,34,29)(28,32,36,39)(35,37,40,38)(3,8)(6,7)(9,11,14,17)(10,15,16,12)(13,19,22,24)(18,23,21,20)(25,27)(26,31)(28,35)(29,33)(30,34)(32,37)(36,40)(38,39)(1,3,5,8)(2,6,4,7)(10,16)(12,15)(13,22)(19,24)(27,34)(28,36)(29,31)(32,39)(3,8)(6,7)(9,12,14,15)(10,17,16,11)(13,20,22,23)(18,24,21,19)(25,28)(26,32)(27,35)(29,38)(30,36)(31,37)(33,39)(34,40)(1,3)(2,7)(4,6)(5,8)(9,10)(11,12)(13,18)(14,16)(15,17)(19,20)(21,22)(23,24)(25,29,30,31)(26,27,33,34)(28,37,36,38)(32,40,39,35)(1,4,5,2)(3,6,8,7)(9,13)(10,18)(11,19)(12,20)(14,22)(15,23)(16,21)(17,24)(25,27)(26,31)(28,35)(29,33)(30,34)(32,37)(36,40)(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.