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)(11,17)(12,13)(14,18)(15,21)(16,22)(19,23)(20,24)(25,26,31,36)(27,35,30,32)(28,29,34,33)(37,38,39,40)(1,3,5,7)(2,4,8,6)(9,11)(10,15)(12,19)(13,20)(14,21)(16,23)(17,18)(22,24)(25,27,31,30)(26,32,36,35)(28,37,34,39)(29,40,33,38)(1,3)(2,6)(4,8)(5,7)(25,28,31,34)(26,33,36,29)(27,37,30,39)(32,38,35,40)(1,3,5,7)(2,4,8,6)(9,12,14,22)(10,16,18,13)(11,19,21,24)(15,23,17,20)(25,28)(26,33)(27,37)(29,36)(30,39)(31,34)(32,38)(35,40)(1,3)(2,4)(5,7)(6,8)(9,13,14,16)(10,12,18,22)(11,20,21,23)(15,19,17,24)(25,29,31,33)(26,34,36,28)(27,38,30,40)(32,37,35,39)(1,4)(2,7)(3,8)(5,6)(9,11)(10,17)(12,19)(13,23)(14,21)(15,18)(16,20)(22,24)(25,30,31,27)(26,35,36,32)(28,39,34,37)(29,38,33,40)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.