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