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