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