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