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