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)(11,16)(12,22)(13,18)(14,15)(17,21)(19,24)(20,23)(26,28)(27,32)(30,38)(37,40)(1,3,4,7)(2,5,6,8)(10,15)(13,22)(16,17)(20,24)(25,26,31,28)(27,34,32,29)(30,33,38,36)(35,40,39,37)(1,2)(3,5)(4,6)(7,8)(9,11,14,21)(10,16,15,17)(12,19,18,23)(13,20,22,24)(25,27)(26,29)(28,34)(30,35)(31,32)(33,37)(36,40)(38,39)(9,11)(10,17)(12,23)(13,20)(14,21)(15,16)(18,19)(22,24)(25,28,31,26)(27,34,32,29)(30,36,38,33)(35,40,39,37)(1,3)(2,5)(4,7)(6,8)(9,12,14,18)(10,13,15,22)(11,19,21,23)(16,20,17,24)(25,29,31,34)(26,32,28,27)(30,37,38,40)(33,39,36,35)(1,2)(3,5)(4,6)(7,8)(9,13)(10,18)(11,20)(12,15)(14,22)(16,23)(17,19)(21,24)(25,30)(26,33)(27,35)(28,36)(29,37)(31,38)(32,39)(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.