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