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