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