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