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