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