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