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