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