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