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