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