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