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)(11,16)(12,17)(13,21)(14,15)(18,23)(19,20)(22,24)(25,26)(27,36)(28,33)(29,32)(30,34)(31,35)(37,38)(39,40) involution — undirected(1,2,4,6)(3,5,8,7)(10,15)(12,16)(18,21)(20,22)(25,27,31,29)(26,32,35,36)(28,37,34,39)(30,38,33,40)(1,2)(3,5)(4,6)(7,8)(10,15)(11,17)(18,21)(19,24)(25,28,31,34)(26,33,35,30)(27,37,29,39)(32,40,36,38)(1,3)(2,5)(4,8)(6,7)(9,11,14,17)(10,16,15,12)(13,19,23,24)(18,22,21,20)(9,12,14,16)(10,17,15,11)(13,22,23,20)(18,19,21,24)(25,29,31,27)(26,32,35,36)(28,39,34,37)(30,38,33,40)(9,13,14,23)(10,18,15,21)(11,19,17,24)(12,20,16,22)(25,30,31,33)(26,34,35,28)(27,38,29,40)(32,39,36,37)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.