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