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