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