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