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