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