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