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