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