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