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