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