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