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