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