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