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