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