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