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)(25,26)(27,36)(28,38)(29,33)(30,37)(31,32)(34,39)(35,40) involution — undirected(1,2,5,8)(3,4,7,6)(9,11,15,12)(10,16,17,13)(14,19,24,20)(18,23,22,21)(26,32)(27,29)(34,38)(35,37)(1,3)(2,6)(4,8)(5,7)(10,17)(11,12)(18,22)(19,20)(25,27,31,29)(26,33,32,36)(28,35,39,37)(30,34,40,38)(1,4)(2,7)(3,8)(5,6)(9,12,15,11)(10,13,17,16)(14,20,24,19)(18,21,22,23)(25,28,31,39)(26,34,32,38)(27,37,29,35)(30,36,40,33)(1,3)(2,4)(5,7)(6,8)(9,13)(10,12)(11,17)(14,23)(15,16)(18,19)(20,22)(21,24)(25,29,31,27)(26,33,32,36)(28,35,39,37)(30,38,40,34)(1,4)(2,7)(3,8)(5,6)(9,14,15,24)(10,18,17,22)(11,19,12,20)(13,21,16,23)(25,30)(26,35)(27,34)(28,36)(29,38)(31,40)(32,37)(33,39)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.