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