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)(11,12)(13,21)(14,17)(15,19)(16,24)(18,22)(20,23)(26,32)(28,38)(33,35)(36,39)(2,3)(6,7)(9,11,14,19)(10,12,17,15)(13,18,24,23)(16,20,21,22)(25,26)(27,33)(28,34)(29,35)(30,36)(31,32)(37,38)(39,40)(1,3,5,2)(4,7,8,6)(9,11)(10,15)(12,17)(13,18)(14,19)(16,22)(20,21)(23,24)(25,27,31,29)(26,33,32,35)(28,36,38,39)(30,37,40,34)(1,4)(2,6)(3,7)(5,8)(9,12,14,15)(10,11,17,19)(13,22,24,20)(16,23,21,18)(25,28)(26,34)(27,36)(29,39)(30,33)(31,38)(32,37)(35,40)(9,11)(10,12)(13,23)(14,19)(15,17)(16,22)(18,24)(20,21)(25,29,31,27)(26,35,32,33)(28,36,38,39)(30,37,40,34)(9,13,14,24)(10,16,17,21)(11,18,19,23)(12,20,15,22)(25,30)(26,36)(27,37)(28,35)(29,34)(31,40)(32,39)(33,38)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.