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