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