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