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