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