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