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