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