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