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