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