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