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