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