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