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