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