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