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