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