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