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