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