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)(11,17,19,15)(12,16,22,20)(18,24,21,23)(25,26)(27,34)(28,36)(29,31)(30,33)(32,37)(35,39)(38,40)(1,2,4,6)(3,5,8,7)(10,14)(15,17)(16,20)(23,24)(25,27,30,29)(26,31,33,34)(28,35,37,38)(32,39,36,40)(1,2)(3,5)(4,6)(7,8)(10,14)(15,17)(16,20)(23,24)(28,37)(32,36)(35,38)(39,40) involution — undirected(1,3)(2,5)(4,8)(6,7)(9,10)(11,15)(12,20)(13,14)(16,22)(17,19)(18,24)(21,23)(25,28,30,37)(26,32,33,36)(27,35,29,38)(31,39,34,40)(9,11,13,19)(10,15,14,17)(12,21,22,18)(16,24,20,23)(25,26)(27,31)(28,32)(29,34)(30,33)(35,39)(36,37)(38,40)(9,12,13,22)(10,16,14,20)(11,18,19,21)(15,23,17,24)(25,29,30,27)(26,31,33,34)(28,35,37,38)(32,40,36,39)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.