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