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