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