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