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