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)(27,35,36,31)(28,37,38,33)(29,34,39,40)(1,2)(3,8)(4,6)(5,7)(9,11,14,19)(10,15,16,24)(12,18,21,22)(13,20,23,17)(25,27,30,36)(26,31,32,35)(28,29,38,39)(33,34,37,40)(1,3)(2,6)(4,5)(7,8)(10,16)(11,19)(12,21)(13,23)(26,32)(28,38)(29,39)(31,35) involution — undirected(3,4)(6,8)(9,12)(10,17)(11,18)(13,15)(14,21)(16,20)(19,22)(23,24)(25,28,30,38)(26,33,32,37)(27,29,36,39)(31,34,35,40)(1,4,5,3)(2,6,7,8)(9,11)(10,15)(12,22)(13,20)(14,19)(16,24)(17,23)(18,21)(25,29)(26,34)(27,28)(30,39)(31,33)(32,40)(35,37)(36,38)(1,2)(3,8)(4,6)(5,7)(9,13,14,23)(10,18,16,22)(11,20,19,17)(12,15,21,24)(25,26)(27,31)(28,33)(29,34)(30,32)(35,36)(37,38)(39,40)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.