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