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