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