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