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