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