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