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