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