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