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