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