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