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