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