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