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