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