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