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