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