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