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