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