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