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