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