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