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