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