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