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