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