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