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