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