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