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