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