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