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