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