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