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