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