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