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