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