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