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