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