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