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