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