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