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