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