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