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