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