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