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